Humans are undoubtedly capable of scanning a very wide field of vision by swiveling their eyes, but while the eyes are not moving it is only possible for information from a small fraction of this field of vision to actually register in the consciousness of the subject. This fraction, referred to here as the primary field of vision, typically extends azimuthally through an angle of about 40°. If the driver of a motor vehicle keeps his gaze fixed firmly on an object, for example a traffic sign he wants to read, it is no longer assured that he will reliably be aware of possible sources of danger that are located outside of his primary field of vision, that is to say with an angular separation of more than 20° from the object of his attention.
A driver assistance system that is capable of detecting at least the direction from the point of view of a motor vehicle driver in which a hazard or source of danger outside the vehicle is located, and displaying an arrow symbol on the front windscreen of the vehicle indicating the direction in which the driver must look to see the detected danger source is known from DE 10 2007 045 932 A1. A further warning signal can be displayed in the windscreen next to the intersection point with a line that connects the driver and the danger source, to warn the driver of danger source explicitly when he has adjusted his view to look in the direction of the danger source.
This conventional driver assistance system requires the driver to first become actively aware of the arrow signal and to understand it. If he then changes his view to look in the direction indicated by the arrow signal, sooner or later the second warning signal or the danger source will come into his field of vision. The conscious awareness and evaluation of the arrow signal, and the subsequent search of the windscreen for the second warning signal takes a considerable time, the length of which depends on the driver's ability to concentrate.